Leaked documents from Brussels revealed what the London-based Guardian newspaper described as a devastating point-by-point rejection of the deal put forward last week by Prime Minister Boris Johnson.
Speaking during a visit Monday to Watford Hospital, north of London, Johnson defended his deal.
"Our proposal is very fair, very reasonable. What we are saying to our friends (the EU) is, this is a very generous, fair and reasonable offer that we have made. What we would like to hear from you now is what your thoughts are. And if you have issues with any of the proposals that we've come up with, then let's get into the detail and discuss them," he told reporters at the hospital.
Johnson said his proposals respected the peace process in Northern Ireland and makes sure there will be no hard border and no checks at the border between Northern Ireland and Ireland.
"That's a big step forward, big advance, big compromise by the UK government," he said.
The documents list nine potential issues with Johnson's proposals, mainly related to the future trading relations between Northern Ireland and the neighboring Irish Republic.
The European commission said Monday it plans to take stock later this week and make an assessment of London's Brexit plan.
At its regular daily briefing, European Commission spokeswoman Mina Andreeva said talks would continue this week to give London the opportunity to present its Brexit proposals in more detail.
One political commentator said it now seems a case of who gives in first, London or Brussels, in the quest to end the Brexit deadlock.
Both sides see talks this week as crucial as they try to hammer out a new Brexit agreement ahead of a summit of European leaders on Oct. 17-18.
According to the Daily Telegraph Monday night, British negotiators provided their EU counterparts with further explanation as to how the British proposal to replace the Irish border backstop will work.
Talks will continue Tuesday in Brussels, British sources confirmed after hours of intensive talks Monday.
While both London and Brussels batted their respective corners, in Scotland campaigners failed in their legal bid to win an order saying Johnson must seek an extension of Britain's departure date from Europe if there is no agreement on a deal by Oct. 19.
Lord Pentland, in his judgement at Scotland's highest civil court, the Court of Session, said that as the British government had told the court it would comply with the government order to seek an extension if needed, there was no need for a court ruling to force them to do it.
Joanna Cherry, Scottish Parliament member from the Scottish National Party, one of the three people who brought the case, said they had succeeded through the case in forcing the Conservative government to concede that Johnson will comply with the law, and promise to send a letter requesting a Brexit extension.
"Given Boris Johnson's slippery track record of acting unlawfully, and the contradictory statements issued by the British government, we do not trust the Conservative leader or believe he can be taken at his word to obey the letter and spirit of the law," Cherry added.
She said they will appeal the decision, and expect the appeal to be heard Tuesday.
Three judges will hear the appeal and a case in which they will be asked to use rarely applied powers to sign a letter to Brussels if the prime minister fails to send the letter himself.
The powers available to the court in what is known as a "nobile officium" case, are not available in England which has a different legal system to Scotland.
It means if Johnson sticks to his public statement that he "would rather die in a ditch than seek a Brexit extension," the court, if it supports the application, would send the letter on his behalf.